[英]SQL Query to join multiple tables
I have 4 tables that I need to connect in order to get the reports that I need. 我有4个表需要连接才能获得我需要的报告。 But I'm confused on how to write the query.
但我对如何编写查询感到困惑。 Below are the sample of the tables:
以下是表格的示例:
Client Table 客户表
client_id | client_name | con_id
----------:|:-------------:|:-------
1 | ABC | 1
2 | DEF | 1
3 | GHI | 2
Consultant 顾问
con_id | con_name
-------:|:---------
1 | Ani
2 | Robby
Perm 彼尔姆
pid | client_id | date
----:|:-----------:|:-----------
1 | 1 | 2014-08-09
2 | 1 | 2014-03-02
3 | 2 | 2014-03-02
Temp 温度
tid | client_id | date
----:|:-----------:|:-----------
1 | 2 | 2013-02-09
2 | 3 | 2011-03-02
3 | 3 | 2012-04-02
The end result of the report that I want to show is something like this: 我要展示的报告的最终结果是这样的:
client_id | client_name | perm(COUNT) | temp(COUNT) | con_name
----------:|:-------------:|:-------------:|:-------------:|:---------
1 | ABC | 2 | 0 | Ani
2 | DEF | 1 | 1 | Ani
3 | GHI | 0 | 2 | Robby
I'm trying to use the LEFT OUTER JOIN
, but I don't get the result that I want. 我正在尝试使用
LEFT OUTER JOIN
,但我没有得到我想要的结果。 Can anyone help me to figure out the query? 任何人都可以帮我弄清楚查询吗? thanks in advanced.
提前致谢。
this is a simple outer join query with count and group by,just join your client
table with the related ones and count only the distinct associations 这是一个带有count和group by的简单外连接查询,只需将您的
client
表与相关联的表连接起来,并仅计算不同的关联
select
c.client_id,
c.client_name,
count(distinct p.pid) perm_count,
count(distinct t.tid) temp_count,
cn.con_name
from client c
left join Consultant cn on(c.con_id = cn.con_id)
left join Perm p on(c.client_id = p.client_id)
left join `Temp` t on(c.client_id = t.client_id)
group by c.client_id
Fiddle Demo
你应该在一个sql中通过joinig all query连接所有表。参见链接http://www.w3resource.com/sql/joins/using-a-where-cluase-to-join-two-tables-related-by-一个单柱主键或- foriegn密钥-pair.php
SELECT a.client_id as client_id, a.client_name as client_name,
a.con_id as client_con_id,
b.con_id as con_id,
b.con_name as con_name,
c.pid as perm_id,
c.client_id as perm_client_id
c.date as perm_date
d.tid as temp_id,
d.client_id as tem_client_id
....Anthing that you want to select .... ....你要选择的Anthing ....
from client_table a
Inner join Consultant_table b on a.client_con_id = b.con_id
Inner join perm_table c on a.client_id= c.perm_client_id
Inner join Temp_table d on....
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.